CVE-2026-16103
This allows an attacker with valid client credentials to obtain access and refresh tokens for a user account that has been locked due to brute-force protection, provided the authentication request was started before the lockout occurred and was approved…
Does this matter?
Lower severity and a low EPSS score (0.34%). Track it; it rarely justifies an emergency change on its own.
Description
A flaw was found in the keycloak-services component of Keycloak. This issue is an incomplete fix for CVE-2026-9798, where brute-force protection checks were added to the Client-Initiated Backchannel Authentication (CIBA) initiation handler but were omitted from the token redemption handler. This allows an attacker with valid client credentials to obtain access and refresh tokens for a user account that has been locked due to brute-force protection, provided the authentication request was started before the lockout occurred and was approved by the user.
- CVSS 3.1
- 4.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
- EPSS
- 0.34% probability · 28th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-305, CWE-841
- Affected
- redhat/build of keycloak
- Source
- secalert@redhat.com
References
- https://access.redhat.com/security/cve/CVE-2026-16103Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2501736Issue Tracking, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.